The above new compounds are racemic intermediates of thienamycin and other compounds of similar structure. The preparation of thienamycin and PS-5 from the compounds of the formula (X) is shown on the next page. ##STR3##
Thienamycin is an antibiotic of broad spectrum. The microbiological preparation of this antibiotic is disclosed in U.S. Pat. No. 3,950,357 and the synthesis thereof in Published German Patent Specification No. 2,751,597.
The first step of the above synthesis has a yield below 10% and therefore the process is very uneconomic.
The microbiological preparation of PS-5 having similar effect and of related compounds is described in Japanese Patent Specification No. 5 4151-598 and the synthesis thereof is reported by Kametani et al. [J. Chem. Soc. Perkin I. 2228 (1981)]; the yields, however, are low.